1. Field of the Invention
The present invention is directed to a dielectric material and a process of insulating a semiconductor device using same. More specifically, the present invention is directed to a dielectric material prepared by introducing liquid or supercritical carbon dioxide into a polymeric dielectric film and employing the dielectric material to insulate semiconductor devices.
2. Background of the Prior Art
The explosive growth in complementary metal oxide semiconductors (CMOS) has corresponded with a continuing decrease in size of such devices. This decrease in CMOS size has been accompanied by thinner and thinner insulating film layers disposed between CMOSs in electrical assemblies. The requirement that insulating layers be provided as exceedingly thin films has occasioned increased numbers of electrical assembly failures due to electrical shorting. These failures, of course, are due to the inadequate insulating properties of such thin insulating materials.
This problem has not gone unnoticed in the art. Thus, many products and processes have been developed to provide more effective insulating materials having lower dielectric constants. Attention is directed to U.S. Pat. Nos. 5,548,159; 5,965,679; 5,965,934; and 6,218,497 which describe polymers having low dielectric constants designed for use in semiconductor applications. Among the polymers developed for use in this application are polyimides, fluorinated polyimides, polyorganohydridosilane, polysiloxanes, polyphenylenes, divinylsiloxane-bisbenzocyclobutene copolymers, polybenzil and polyarylethers.
The use of these polymeric materials has improved insulating characteristics and has reduced short failures of semiconductor-containing electrical assemblies. However, the employment of these newly developed polymers has not completely overcome the aforementioned “shorting” problem. That is, although the dielectric properties of these new polymers are lower than those used heretofore, the degree of electrical insulation provided by these newly developed polymers is oftentimes still inadequate to ensure against shorts between semiconductor devices separated by films of these polymers.
The aforementioned discussion, emphasizing the inability of polymeric films of dielectric materials to insulate between semiconductor devices, suggests that something more than the development of new polymers is required to provide adequate insulating capacity. Certainly, recent developments suggest a need in art for the development of polymeric materials having even lower dielectric constants than those developed to date to satisfy the stringent requirements imposed upon insulating materials used in semiconductor-containing electrical assemblies.